City F and City G is 624 km apart. Zane left City F for City G at 11.00 a.m. travelling at an average speed of 78 km/h. Albert left City F later than Zane and caught up with him at 3.00 p.m. Albert was travelling at a speed of 117 km/h.

1. At what time did Albert leave City F?
2. How much later did Zane arrive in City G than Albert? Express your answer in h as a fraction or mixed number.

(a)
From 11.00 a.m. to 3.00 p.m. = 4 h

Distance that Zane covered when Albert caught up with Zane
= 4 x 78
= 312 km

Time that Albert took to travel 312 km
= 312 ÷ 117
= 2²₃ h

1 h = 60 min
²₃ h = ²₃ x 60 = 40 min
2²₃ h = 2 h 40 min

Time that Albert left City F:
2 h 40 min before 3.00 p.m. = 12.20 p.m.

(b)
Remaining distance that they had to cover to reach City G
= 624 - 312
= 312 km

Duration that Albert had to travel before reaching City G
= 312 ÷ 117
= 2²₃ h

Duration that Zane had to travel before reaching City G
= 312 ÷ 78
= 4 h

Duration that Zane took to arrive later than Albert in City G
= 4 - 2²₃
= 1¹₃ h

Answer(s): (a) 12.20 p.m.; (b) 1¹₃ h